1. Field of the Invention
The invention generally relates to a telescoping syringe with a plunger extendible from and retractable into a barrel and more particularly is concerned, for example, with an improved valve mechanism between reservoirs within a syringe. Specifically, the valve is extendible from and retractable onto one end of the plunger. The valve prevents leakage of a fluid from the syringe prior to extension of the plunger from the barrel. The valve also permits transfer of a fluid from a first reservoir within the plunger into a second reservoir within the barrel during extension of the plunger from the barrel. The valve further facilitates ejection of a fluid from the second reservoir during retraction of the plunger into the barrel.
2. Background
A variety of telescoping syringes are known within the art. Conventional syringes are often used in connection with a vial containing a fluid, typically a medication or other injectable or ejectable fluid, whereby the user draws fluid into the syringe. It is common for some syringes to be packaged as prefilled devices, whereby a syringe is sold to the end user prefilled with fluid already residing within the syringe. Prefilled syringes are beneficial in that such devices eliminate one or more steps required for proper use thereby reducing the cost of use and in that such devices control the quantity of fluid delivered thereby reducing errors associated with use.
However, prefilled syringes and packaging therefore tend to be bulky because the barrel is filled with fluid requiring the plunger to extend from the barrel. The elongated nature of prefilled syringes and packaging therefore increases non-use costs associated with shipping and storage by virtue of the greater volume occupied by the prefilled device.
Medical applications of prefilled syringes are particularly problematic in that the fluid contained within the syringe often must be safeguarded from theft via storage within a locked cabinet or the like. The space available for secured storage is often limited and costly, thus creating a need for prefilled syringes to have a smaller footprint with and without packaging.
It is further understood that the related arts do not provide a mechanism that reliably and simply facilitates proper function of a telescoping syringe. For example, known telescoping syringes are mechanically complex in design and use, functionally unreliable, difficult to manufacture, and/or costly. Furthermore, known telescoping syringes are prone to leakage and unable to prevent or minimize air surrounding the syringe from entering a second or ejection reservoir as fluid is transferred from a first or storage reservoir to the ejection reservoir.
For at least the reasons discussed above, the benefits and advantages of telescoping-type syringes have yet to be completely realized.
Accordingly, what is required is a telescoping syringe that is mechanically simple in design and use, functionally reliable, easily manufactured, and less costly to package, ship, store and use.